After an armed man raped three women at Glen Burnie apartment buildings, county police are warning apartment dwellers to be careful in and around home.

Police have increased patrols at the two Glen Burnie apartments where the incidents occurred, but say they can't be everywhere all the time.

"It's up to the individual to be extra cautious right now and conscious of their surroundings much more than they normally would be," said Officer Carol Frye, police spokeswoman.

"I don't want to scare everybody, but he is out there, he is dangerous and we haven't caught him yet."

Friday, reserve police officers went to several Glen Burnie apartment complexes -- including Gate-water Landing and Americana Southgate, where the incidents occurred -- and posted fliers with a composite sketch and description of the man police believe raped three women in Glen Burnie and two in Northern Virginia, and sexually assaulted another Northern Virginia woman.

Managers at the apartments said they have taken measures to improve security.

"We put out a letter [about the assaults] and hand-delivered it to every apartment," said Karen Loverde, property manager at Americana Southdale, where two maintenance workers were raped while cleaning laundry rooms.

"We requested that residents keep the laundry room door closed because that's an open invitation to anyone who doesn't have a key," she said, adding that the doors automatically lock when closed. "You have to take some responsibility to try to make yourself safe."

Employees now work with a partner, Loverde said.

At Gatewater Landing, where the first assault occurred in a woman's apartment April 10, property managers are sending letters informing residents about the related assaults.

They have also increased patrol services in the complex, said Kristin Laidig, district manager for the company that manages the apartments.

Fliers posted in Glen Burnie apartments urge residents to pair up with a friend or neighbor when using common areas such as the laundry rooms and community rooms, and not to open the door for people they don't recognize or aren't expecting.

All six of the assaults were during the day. In four cases, the man approached the women in laundry rooms. Two others were assaulted in their apartments, but in one case, the attacker entered the apartment by posing as a maintenance worker, police said.

"The detectives are working diligently to try to come up with a common denominator to lead us to this guy," Frye said. "It's probably right now our top priority."

Other tips for apartment dwellers:

Have apartment and car keys in hand before reaching the car or home, and lock the door immediately.

Reduce vulnerability by keeping at least one hand free when carrying packages, even if it requires a second trip.

Park in a well-lighted area and scan the parking lot before getting out.

If someone is following, go into a store or other area with people, or knock on a door for help. Draw attention.

Be aware of others. Don't daydream.

When feeling uncomfortable or threatened, go with your instincts and leave.